I don’t think it went so cheap at $355? It went for an above average price for non-mint. Unless I missed something, the damage didn’t look that bad to me.
http://ravnheart.com/windstone/index.php?act=details&id=105
http://ravnheart.com/windstone/index.php?act=details&id=359
The price is always going to fluctuate, depending on who’s looking to buy one at the time and how deep their pockets are. If it’s non-mint, the extent of the damage will affect the price. Even then, it depends on if the buyer has repair skills or if they will have to send it to somebody for repair.